Air box for furnaces



Feb.'1 9, 1935.

T. B. STILLMAN 1,991,711

AIR BOX FOR FURNACES Filed March 10, 1931 2 Sheets-Sheet l INVENTOR Feb. 19, 1935. T s N 1,991,711

AIR BOX-FOR FURNACES Filed March 10, 1951 2 Sheets-Sheet 2 VIIIIIIIII/I /IIIIIIIIII IIIIIIII/I IIIIIIIIII/ I IIIIIIIIIIII/t III/III,

a HE? Patented Feb. 19, 1935 um STATES AIR BOX FOR F IIRNACES I Thomas B. Stillman, South Orange, N. J assignor to The Babcock &

Wilcox Company, Bayonne,

N. J., a corporation of New Jersey Application March 10, 1931, Serial No. 521,444

4 Claims.

This invention relates to an air box for supplying air for combustion purposes to a furnace above a chain grate stoker, and is particularly applicable when such installations are made under boilers for marine purposes. It has been found that when a ship is maneuvering, or is tied at the dock, or under any other'conditions when it is not necessary to pass the air through the box for purposes of combustion, with the construction of box heretofore used theradiant heat from the fuel bed on the chain grate stoker and from the furnace walls in general penetrates the air box to such anextent that the metal of the box softens, whether made from specially treated I?) sheets or high temperature alloys, with the result that the air box sags toward the fire, and is seriously deformed, if not rendered inoperative. By the present invention this objection is obviated by cooling the air box continually throughout the operation of the boiler, no matter what the combustion conditions might be, by mounting it in heat transferring relationship to a water box.

The invention will be understood from the description in connection with the accompanying drawings in which Fig. 1 is a vertical section through a boiler furnace showing an illustrative embodiment of the invention; Fig. 2 is a side view of an embodiment of the invention partly broken away; Fig. 3 is a section along'the line 3-3 of Fig. 2 and Fig. 4 is a section along the line 4-4 of Fig. 2.

In the drawings reference character 1 indicates a furnace, in the lower portion of which a stoker 2 having air chambers 3 between the runs thereof is located. f

A boiler may be located above the furnace. The one illustrated in Fig. 1 of the drawings is of the water tube type having downtake headers 4 and uptake headers 5 connected by inclined tubes 6. Water boxes 7 and 8 are provided at the front and sides of the stoker 2, these water boxes being connected to the water circulation system of the boiler by connections 9 and 10. A bafile 11 extends along the lowermost row of tubes 6 for some distance from the lower headers 4 to direct the hot products of combustion from the furnace in a pass across the upper portions of the tubes 6. Nipples 12 connect the lower ends of the headers 4 to a cross box or mud drum 13. The parts thus far described are old in the art.

A plate 15 is attached to the furnace side of the cross box 13. This plate may be made in sections provided with openings 16 and may be attached to the cross box 13 by being welded thereto as indicated at 1'7. A horizontally extending flange 18 is provided at the lower edge of the plate 15 and the upper edge of this plate extends a short distance beyond the top side of the cross box 13. Slots 19 are provided at intervals in the flange l8 and the corresponding 5 portions of the lower edge of the plate 15.

An air box 20 is provided for supplying air to the furnace above the stoker. This air box may be provided with internal longitudinal ribs 21 to promote the transfer of heat from the metal 10 of the box to the air passing therethrough. The lower portion of the side of the air box 20 toward the furnace is made sloping and is provided with a series of holes 22 through which streams of air pass from this box in a downward and forward direction into the furnace. An air conduit 23 which may lead from any convenient source of air-under pressure leads to the air box 20.

Tile supporting members or bulb beams 25 are provided with lugs 26 near one end thereof. 20 These lugs extend into the slots 19 when the members 25 are in place. The lugs 26 are provided with holes through which pins 27 pass and rest upon the flange 18 to support the furnace ends of the members 25. The members 25 are .25 provided with lugs 28 at their other ends, these lugs being attached to flanges 29 on the'boiler setting 30. Bulbs or'enlarged portions 31 are, provided at the lower edges of the members 25 to support tile. Blocks of tile 32 are supported 30 below the air box 20 and the cross box 13. These tile have grooves 33 along the sides into which the bulbs 31 extend for supporting the tile.

The cross box 13 being connected to the downtake headers 4 is kept relatively cool by water 35 from the circulation system of the boiler and this box in turn keeps the air box 20 sufficiently cool to avoid the danger of its being destroyed by the heat of the furnace.

I claim:

1. In a boiler having downtake and uptake headers and inclined tubes connected to said headers, a furnace, an air box for supplying air to said furnace, and cooling means for said air box connected to some of said headers and lo- 45 cated on the other side of said air box from said furnace.

2. In a boiler having downtake and uptake headers and inclined tubes connected to said headers, a furnace, an air-box and a cross box 50 connected to the lower ends of said downtake headers, said cross box having water connections with said headers and said air box being supported by said cross box.

3. In a boiler having downtake and uptake 5 headers and inclined tubes connected to 'said headers, a furnace, an air box for supplying air to said furnace and a cross box connected to the lower ends of said downtake headers, said air 5 box being supported by said cross box, and tile below said air box also supported by said cross box.

4. In a boiler having downtake and uptake headers and inclined tubes connected tosaid headers, a furnace, a cross box connected to the THOMAS 

